Prevalence of Bacteria and Antimicrobial Resistance Genes in Hospital Water and Surfaces

Assessment of antimicrobial resistance, biofilm formation, and surface modification potential in hospital strains of Pseudomonas aeruginosa and Klebsiella pneumoniae

The occurrence of healthcare-associated infections is a multifactorial phenomenon related to hospital space contamination by bacteria. The ESKAPE group, specifically Pseudomonas aeruginosa and Klebsiella pneumoniae, play a relevant role in the occurrence of these infections. Therefore, comprehensive research is needed to identify characteristics that justify the prevalence of these species in the healthcare environment. In this line, the study aimed to determine the antimicrobial resistance, biofilm formation, and the potential for polymer degradation in a collection of 33 P. aeruginosa strains and 2 K. pneumoniae strains sampled from various equipment and non-critical surfaces in a Portuguese hospital. Antimicrobial susceptibility tests revealed that none of the strains was categorized as multidrug-resistant (non-MDR). An assessment of their biofilm-forming capabilities indicated that 97 % of the strains exhibited biofilm-producing characteristics. Notably, within this group, the majority of P. aeruginosa and half of K. pneumoniae strains were classified as strong biofilm producers. Furthermore, the strains were evaluated for their potential to cause damage or change medical devices, namely infusion sets, nasal cannula, and urinary catheters. Three P. aeruginosa strains, two strong and one moderate biofilm producers, showed the highest ability to modify surfaces of the nasal cannula and infusion sets. Additionally, the Chi-square test revealed a statistically significant relationship between the presence of P. aeruginosa strains and the water accession spots. In conclusion, this work suggests that bacteria from this group hold a significant ability to grow in the healthcare environment through the degradation of non-critical materials. This suggests a potential concern for the persistence and proliferation of these organisms in hospital environments, emphasizing the importance of robust infection control measures to mitigate the risks associated with bacterial growth on such surfaces.

A systematic review and meta-analysis of carbapenem resistance and its possible treatment options with focus on clinical Enterobacteriaceae: Thirty years of development in Pakistan

Background

Carbapenem resistance is epidemic worldwide, these last resort antimicrobials are listed in the WHO 'watch group' with higher resistance potential. During the years 2017-18 Pakistan Antimicrobial Resistance Surveillance System reported an increase in carbapenem resistance. However, a comprehensive information on prevalence and molecular epidemiology of carbapenem resistance in Pakistan is not available. This systematic review and meta-analysis is aimed to report the current carbapenem resistance situation in Pakistan and its treatment options.

Methods

In this systematic review and meta-analysis, we investigated the pooled prevalence (PPr) of carbapenem resistance in Enterobacteriaceae and non-Enterobacteriaceae by organizing available data, from Web of Science and PubMed by April 2, 2020, in various groups and subgroups including species, years, provinces, extended spectrum β-lactamase production, clinical presentation, carbapenemase and metallo-β-lactamase production, and New Delhi metallo-β-lactamase (NDM) prevalence. Literature review was updated for the studies publisehd by December 07, 2023. Moreover, we descriptively reviewed the molecular epidemiology of carbapenem resistance in Enterobacteriaceae and non-Enterobacteriaceae in Pakistan. Lastly, we statistically explored different treatment options available for carbapenem resistant infections. We used R package 'metafor' for performing meta-analysis and influence diagnostics and determining treatment options.

Results

From two academic databases Web of Science and PubMed we identified 343 studies. Eighty-eight studies were selected for the systematic review and meta-analysis. Seventy-four studies were selected for phenotypic analysis, 36 for genotypic analysis, and 31 for available treatment options. PPr-ID of 12% [0.12 (0.07, 0.16)] was observed for phenotypic carbapenem resistance in Enterobacteriaceae with more prevalence recorded in Klebsiella pneumoniae 24% [0.24 (0.05, 0.44)] followed by 9% [0.09 (-0.03, 0.20)] in Escherichia coli. During the last two decades we observed a striking increase in carbapenem resistance PPr i.e., from 0% [0.00 (-0.02, 0.03)] to 36% [0.36 (0.17, 0.56)]. blaNDM with PPr 15% [0.15 (0.06, 0.23)] in naive isolates was found to be the fundamental genetic determinant for carbapenem resistance in Enterobacteriaceae in Pakistan. Polymyxin B, colistin, tigecycline, and fosfomycin were identified as the suggested treatment options available for multidrug resistant infections not responding to carbapenems. Various studies reported carbapenem resistance from human, animal, and environment sources.

Conclusion

In conclusion, we found that NDM-1 producing carbapenem resistant Enterobacteriaceae are increasing in Pakistan. Meta-analysis showed that metallo-β-lactamases producing E. coli ST405 and K. pneumoniae sequence type11 are the major resistant clones. Number of reported studies in various subgroups and inconsistency in following CLSI guidelines are the potential limitations of this meta-analysis. A National antimicrobial resistance (AMR) surveillance strategy based on One Health is urgently needed to check any future AMR crisis in Pakistan.

Hospital Acquired Pathogenic Escherichia coli from Clinical and Hospital Water Samples of Quetta Balochistan

A study was conducted to determine the prevalence and drug resistance of Escherichia coli present in urinary tract infected patients and hospital drinking water. A total of eighty urine samples from clinically suspected patients and thirty tap water samples from hospital vicinity were collected and analyzed for the presence of E. coli. The isolates were preliminary identified based on morphological characteristics, biochemical test and further confirmed by polymerase chain reaction (PCR) using uidA primer. Isolates were subjected to antibiogram studies and analyzed for the presence of drug resistance (ESBL blaCTX-M-15, tetA, and TMP-SMX dfrA1) and pathogenicity associated pyelonephritis-associated pili (PAP) and Heat-labile (LT) toxin genes. Urine samples 19/80 (23.75%) and water samples 8/30 (26.7%) were found contaminated with E. coli. It was found that 12/19 (63%) bacterial isolates were extended spectrum beta-lactamase (ESBL) producers in clinical and 6/8 (75%) in water isolates whereas tetracycline resistance in clinical and water isolates was 11/19 (58%) and 6/8 (75%), respectively. The trimethoprim resistance gene was confirmed in 12/19 (63%) in clinical and 2/8 (25%) in water isolates. All the clinical and water isolates were found carrying pili PAP gene. It was concluded that the presence of drug resistant and pathogenic E. coli in clinical and water samples is extremely alarming for public health due to cross contamination and bacterial transfer from clinical samples to water and vice versa.

A Selective Medium for Screening Ceftazidime/Avibactam Resistance in Carbapenem-Resistant Enterobacterales

Ceftazidime/avibactam (CZA) is an alternative antibiotic used for the treatment of infections caused by carbapenem-resistant Enterobacterales (CRE). However, the CZA-resistant CRE strains have been detected worldwide. Therefore, it is critical to screen CZA-resistant CRE strains in colonized patients or a specific population so as to rapidly implement infection control measures to limit their transmission. In this study, we developed a Salmonella-Shigella (SS) CZA-selective medium and assessed its performance to screen for clinical CZA-resistant CRE isolates in both pure-strain specimens and stool samples. A total of 150 non-duplicated isolates, including 75 CZA-susceptible and 75 CZA-resistant CRE pathogens, were tested by using the broth microdilution method and the SS CZA medium, respectively. The bacterial suspensions were serially diluted in the SS CZA medium, which showed excellent screening performance in both pure CZA-resistant CRE strain and the stool samples with the lowest detection limit of 10¹-10² and 10¹-10³ CFU/ml, respectively. Notably, none of the susceptible isolates showed growth even at the highest dilution concentration of 10⁸ CFU/ml. Most importantly, the SS CZA medium demonstrated excellent performance in screening simulated clinical polymicrobial specimens. Moreover, its screening performance was unaffected by the different resistance determinants for tested isolates. Cumulatively, our data suggest that the SS CZA medium can be used as a promising selective medium to screen CZA-resistant CRE, irrespective of their resistance mechanisms.